Clinical Characteristics and Treatment Outcome of Hypocellular Acute Myeloid Leukemia Based on WHO Classification.

The hypocellular acute leukemia is very rare atypical leukemia with frequency of 5-7% among patients with acute leukemias. It mainly occurs in older patients and usually has a myeloid phenotype. It is still unclear whether the outcome of hypocellular acute myeloid leukemia is less favorable than adult acute myeloid leukemia with normal cellularity. We retrospectively analyzed all hypocellular acute myeloid leukemias which were treated in 16 years period, between January 1998 and December 2014. There were 33 patients, 21 male and 12 female. The median age of the patients was 58.9 years (ranging from 19 to 88 years) and median cellularity of bone marrow was 16%. All patients presented with cytopenias with median white blood cell count 1.9 × 109/l, platelets 47.2 × 109/l and hemoglobin 85.9 g/l. Nineteen patients were treated with standard 3 + 7 protocol (daunoblastin 45 mg/m2 1, 3, 5 days, cytosin-arabinozide 100 mg/m2/12 h for 7 days), 5 patients with HDAC protocol and, 3 (9%) with low dose cytosin-arabinoside and in 6 (18.1%) patients only supportive therapy was applied. One patient died on 34 day after treatment with HiDAC, 3 patients after treatment with 3 + 7 regimen in full doses on days 23, 35, and 58 days. Complete remission was achieved in 20/33 (60.60%) patients, with median duration of 14 months. Median overall survival (OS) of the entire cohort was 16 months, and for the treated group 21 months (range 5-67 months). Median OS of patients treated with low dose cytosine-arabinoside was 6 months. The advanced age (p = 0.009, KK = - 0.46, Log rank, p = 0.031) as well as therapy options (Log rank p < 0.0001) shows a significant correlation with OS. We report a cohort of patients with hypocellular acute myeloid leukemia who responded to standard induction chemotherapy as are in standard acute myeloid leukemia.